Partial functions demo

	package functions
	/**
	What is a partial function? From the Scala API: "A partial function of type PartialFunction[A, B]
	is a unary function where the domain does not necessarily include all values of type A.
	The function isDefinedAt allows to test dynamically if a value is in the domain of the function."
	I think it's best compared to using a switch statement in Java or a match expression in Scala
	where you enumerate cases and execute the corresponding block of code. But the main difference
	is that a partial function is just one of those cases (which is why it only handles part
	of the domain) and the sum (orElse) of these partial functions should cover the entire domain.
	Let's assume we let males and females define their own rewarding strategy for work they deliver.
	Males receive a salary depending on the length of their name and females all receive the same salary.
	We can map humans to their respective salary by applying partial function(s)
	**/
	object PartialFunctionDemo {
	abstract class Human(name: String, gender: String)
	case class Male(name: String) extends Human(name, "Male")
	case class Female(name: String) extends Human(name, "Female")
	val maleSalary: PartialFunction[Human, Int] = {
	case Male(name) => name.length * 1000
	}
	val femaleSalary: PartialFunction[Human, Int] = {
	case h: Female => 3500
	}
	def main(args: Array[String]): Unit = {
	val humans = List(Male("Rob"), Female("Sarah"), Male("Thorsten"), Female("Demi"))
	println(humans map (maleSalary orElse femaleSalary))
	}
	}
	/** output printed to console
	List(3000, 3500, 8000, 3500)
	**/

view raw gistfile1.scala hosted with ❤ by GitHub